An indexable drill is a cutting tool which is configured on a tool body so as to replace and mount a cutting insert, and used to process a hole in a workpiece.
In general, in order to improve cutting performance, the indexable drill adopts a structure in which an oil hole is formed in a tool body, and cutting oil is supplied to the oil hole.
Meanwhile, the indexable drill has a structure in which a plurality of cutting inserts is installed. In this case, the plurality of cutting inserts may sometimes include different types of cutting inserts. In more detail, an internal cutting insert is disposed adjacent to a centerline CL, and an external cutting insert is disposed adjacent to an outer circumferential surface of the indexable drill.
As described above, since two or more types of cutting inserts, such as the internal cutting insert and the external cutting insert, are mounted on the indexable drill in the related art, there is an inconvenience of having to handle the plurality of cutting inserts.
On the other hand, it is proposed that a plurality of cutting edges for performing a cutting process may be used for the cutting insert, and the type of product may be named based on the number of available cutting edges.
For example, Korean Patent Application Laid-Open No. 10-2012-0082824 discloses that maximum six cutting edges may be used for the cutting insert. Since the six cutting edges are used for the cutting insert in the related art, the cutting insert may be named a 6-corner product.
However, the 6-corner product in the related art has a problem in that an inclination angle RR in a radial direction is a minus (−) angle that is a greatly applied, and as a result, a cutting load is large.
In addition, there is a problem in that the cutting insert, which has the inclination angle RR in the radial direction which is a minus (−) angle that is a greatly applied, degrades surface roughness of a surface to be processed.